After a few WoGE where my stubbornness send me way off (see
WoGE #406), this time it send me (almost) directly to the
spot - the 1256 volcanic eruption basalts east of the Medina's holy city!
Now, my challenge:
Yes, it's very similar to Felix's #406, I know it :) And that's the reason to call for the Schott rule in this challenge (publish time: 03:00:00, Friday 28, March 2014 WET)
So, your goal is to
find out the exact location and the geology of this place and, if you are the first, you can have the honor of presenting the next WoGE.
Rules, tips and previous WoGEs are collected by Felix on his blog and a KML file is available with all WoGEs.
Okay, got it--southern hemisphere with NW-SE structural trends. It's at -15.97, -69.69, near the southwest shore of Lake Titicaca, Peru.
ResponderEliminarThe geologic map
http://www.calameo.com/read/0008201297692676bfe09
shows it as Grupo Puno, a thick (7 km) Tertiary inter-Andean molasse composed of red arkosic sandstones, conglomerates, and shales. In this area it lies relatively conformably above Cretaceous strata, but outside the basin it overlies an angular unconformity. More information is in this article (en español):
http://www.calameo.com/read/0008201297a60950c0de9
This game is sort of addictive . . .
-Nick Van Buer
I just want to add that the Geology of the Lake Titicaca region, Peru and Bolivia has a lot of info about this area and (in page 24 and in the map on page 22) refers this structure as "the Pirín thrust".
EliminarCongrats and bring the new one! :)
Ah, the geologic map I found didn't show that. But it explains why the Tertiary strata are tilted up (probably a footwall syncline) and why the rocks to the SW are full of more complicated folds, if they're part of an older, overthrust hanging wall. Anyway, WoGE 439 is now posted here:
Eliminarhttp://intrusivecomplex.blogspot.com/2014/03/woge-439.html
-Nick